#define NETLINK_F_BROADCAST_SEND_ERROR 0x4
#define NETLINK_F_RECV_NO_ENOBUFS 0x8
#define NETLINK_F_LISTEN_ALL_NSID 0x10
+#define NETLINK_F_CAP_ACK 0x20
static inline int netlink_is_kernel(struct sock *sk)
{
return netlink_lookup_frame(ring, ring->head, status);
}
-static struct nl_mmap_hdr *
-netlink_previous_frame(const struct netlink_ring *ring,
- enum nl_mmap_status status)
-{
- unsigned int prev;
-
- prev = ring->head ? ring->head - 1 : ring->frame_max;
- return netlink_lookup_frame(ring, prev, status);
-}
-
static void netlink_increment_head(struct netlink_ring *ring)
{
ring->head = ring->head != ring->frame_max ? ring->head + 1 : 0;
static void netlink_forward_ring(struct netlink_ring *ring)
{
- unsigned int head = ring->head, pos = head;
+ unsigned int head = ring->head;
const struct nl_mmap_hdr *hdr;
do {
- hdr = __netlink_lookup_frame(ring, pos);
+ hdr = __netlink_lookup_frame(ring, ring->head);
if (hdr->nm_status == NL_MMAP_STATUS_UNUSED)
break;
if (hdr->nm_status != NL_MMAP_STATUS_SKIP)
} while (ring->head != head);
}
+static bool netlink_has_valid_frame(struct netlink_ring *ring)
+{
+ unsigned int head = ring->head, pos = head;
+ const struct nl_mmap_hdr *hdr;
+
+ do {
+ hdr = __netlink_lookup_frame(ring, pos);
+ if (hdr->nm_status == NL_MMAP_STATUS_VALID)
+ return true;
+ pos = pos != 0 ? pos - 1 : ring->frame_max;
+ } while (pos != head);
+
+ return false;
+}
+
static bool netlink_dump_space(struct netlink_sock *nlk)
{
struct netlink_ring *ring = &nlk->rx_ring;
spin_lock_bh(&sk->sk_receive_queue.lock);
if (nlk->rx_ring.pg_vec) {
- netlink_forward_ring(&nlk->rx_ring);
- if (!netlink_previous_frame(&nlk->rx_ring, NL_MMAP_STATUS_UNUSED))
+ if (netlink_has_valid_frame(&nlk->rx_ring))
mask |= POLLIN | POLLRDNORM;
}
spin_unlock_bh(&sk->sk_receive_queue.lock);
err = __netlink_insert(table, sk);
if (err) {
+ /* In case the hashtable backend returns with -EBUSY
+ * from here, it must not escape to the caller.
+ */
+ if (unlikely(err == -EBUSY))
+ err = -EOVERFLOW;
if (err == -EEXIST)
err = -EADDRINUSE;
nlk_sk(sk)->portid = 0;
nlk->flags &= ~NETLINK_F_LISTEN_ALL_NSID;
err = 0;
break;
+ case NETLINK_CAP_ACK:
+ if (val)
+ nlk->flags |= NETLINK_F_CAP_ACK;
+ else
+ nlk->flags &= ~NETLINK_F_CAP_ACK;
+ err = 0;
+ break;
default:
err = -ENOPROTOOPT;
}
netlink_table_ungrab();
break;
}
+ case NETLINK_CAP_ACK:
+ if (len < sizeof(int))
+ return -EINVAL;
+ len = sizeof(int);
+ val = nlk->flags & NETLINK_F_CAP_ACK ? 1 : 0;
+ if (put_user(len, optlen) ||
+ put_user(val, optval))
+ return -EFAULT;
+ err = 0;
+ break;
default:
err = -ENOPROTOOPT;
}
* sendmsg(), but that's what we've got...
*/
if (netlink_tx_is_mmaped(sk) &&
- msg->msg_iter.type == ITER_IOVEC &&
+ iter_is_iovec(&msg->msg_iter) &&
msg->msg_iter.nr_segs == 1 &&
msg->msg_iter.iov->iov_base == NULL) {
err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
struct nlmsghdr *rep;
struct nlmsgerr *errmsg;
size_t payload = sizeof(*errmsg);
+ struct netlink_sock *nlk = nlk_sk(NETLINK_CB(in_skb).sk);
- /* error messages get the original request appened */
- if (err)
+ /* Error messages get the original request appened, unless the user
+ * requests to cap the error message.
+ */
+ if (!(nlk->flags & NETLINK_F_CAP_ACK) && err)
payload += nlmsg_len(nlh);
skb = netlink_alloc_skb(in_skb->sk, nlmsg_total_size(payload),
NLMSG_ERROR, payload, 0);
errmsg = nlmsg_data(rep);
errmsg->error = err;
- memcpy(&errmsg->msg, nlh, err ? nlh->nlmsg_len : sizeof(*nlh));
+ memcpy(&errmsg->msg, nlh, payload > sizeof(*errmsg) ? nlh->nlmsg_len : sizeof(*nlh));
netlink_unicast(in_skb->sk, skb, NETLINK_CB(in_skb).portid, MSG_DONTWAIT);
}
EXPORT_SYMBOL(netlink_ack);